This package provides an orphan instance that allows you to use HUnit assertions as QuickCheck properties.
Why would you want to do this?
Example: Setting an environment variable with setEnv and then getting the
value back with getEnv should work for arbitrary key–value pairs. Sounds
like a job for QuickCheck, huh?
import Test.QuickCheck
import Test.QuickCheck.IO ()
import Test.Hspec.Expectations (shouldReturn)
import System.SetEnv (setEnv)
import System.Environment (getEnv)
prop_setEnv k v = validKey k && validValue v ==> do
setEnv k v
getEnv k `shouldReturn` v
validKey k = (not . null) k && '\NUL' `notElem` k && '=' `notElem` k
validValue v = (not . null) v && '\NUL' `notElem` vghci> quickCheck prop_setEnv
+++ OK, passed 100 tests.
You can e.g. use HUnit's @?=
ghci> import Test.QuickCheck
ghci> import Test.QuickCheck.IO
ghci> import Test.HUnit
ghci> quickCheck $ \x -> x + 23 @?= 23
*** Failed! (after 3 tests and 2 shrinks):
expected: 23
but got: 24
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or Hspec's shouldBe
ghci> import Test.QuickCheck
ghci> import Test.QuickCheck.IO
ghci> import Test.Hspec.Expectations
ghci> quickCheck $ \x -> x + 23 `shouldBe` 23
*** Failed! (after 3 tests and 2 shrinks):
expected: 23
but got: 24
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